Method of making valves



A. T. coLWELL METHOD OF MAKING VALVES Filed May 20, 1951 g., j Z 1 3Sept. 21, 1937.

MLM,...

3 y f F0, w 0 T \j v Patented Sept. 2l, i937 METHOD 0F MAKING VALVESArchie T. Colwell, Cleveland, 0hio, assgnor to Thompson Products,llncorporated, Cleveland, Ohio, a corporation of Ohio Application May20, 1931, Serial No. 538,785

3 Claims.

This invention relates to the manufacture of valves and in particular toa process for making copper cooled exhaust valves for internalcombustion engines.

Temperatures attained in the combustion chambers of automotive enginesclosely approximate the temperatures to which the metals used in themanufacture of valves are heated in such manufacture. The gases whichpass through the 10 exhaust valves maintain the exhaust passageway 15the metal of the valves.

at a temperature of around 1600 F. for ordinary engine speeds. Thesegases have a very destructive effect on the valves, causing corrosionand warping and producing a destructive change in Since these gases aredirected against a portion of the valves which includes the upperportion of its stem and the lower portion of its head, it has beenaproblem for valve manufacturers to devise a means of cooling thisportion of the valve.

This cooling has been accomplished in several ways, as by providing ashield around this porltion of the valve and by filling Athe interior ofthe valve with a cooling or high heat conducting means.

This invention relates to the latter type of cooled valve and it is anobject of this invention to produce a valve of this type by a methodwhich is inexpensive, expedient and adapted for use in large scaleproduction.

It is a further object of this invention to produce a metallic cooledvalve by a method which insures a perfect bond between the metal of thevalve and the metallic cooling insert.

It is a particular object of this invention to provide a method ofmaking a metallic cooled valve in which the metal of the body of thevalve is shrunk onto an insert metal and welded thereto.

Other and further important objects of this invention will be apparentfrom the following.

description and appended claims.

This invention (in a preferred form) is illustrated in the drawing andhereinafter more fully described.

On the drawing:

Figure l is a sectional view of a metal blank with a recess drilledtherein, used for forming the valve of this invention.

Figure 2 is a sectional View of the blank with an insert therein.

Figure 3 is a sectional view of a suitable form of die blank with apartially extruded valve therein.

Figure 4 is a sectional view of a valve blank after extrusion.

Figure 5 is a sectional view of a valve blank which has been extruded inaccordance with a modiiied form of my invention.

Figure 6 is a sectional view of a completed valve.

As shown on the drawing: i

In carrying out this invention, a blank l is formed as by casting. or bycutting a slug from a bar of rolled stock. A suitable recess 2 isdrilled in the blank l. The recess 2 is preferably cylindrical andconcentric with the blank l extending through one end of the blank andfor a substantial distance within the blank.

The blank I is heated to a forging temperature and an insert 3 is forcedinto the expanded recess 2.

The blank I may be formed of any suitable valve material, such astungsten steel or nickel chromium steel. The insert or slug 3 is formedof a suitable metal which has a. high rate of heat conductivity relativeto that of the metal of the blank. In practice, copper and aluminum havebeen found to be suitable metals from which to form the insert 3. v

The composite metal blank thus formed is headed or extruded to form thefinished valve.

Figure 3 illustrates a suitable die block i for extruding the blank toform the valve. The block d preferably comprises a pair of superimposedmembers 5 and 6, the top member 5 of which is provided with a recess 'iextending for a considerable distance therein. The inner wall of therecess l tapers downwardly and inwardly and ends in an inwardly curvedportion 8 shaped to form the neck of the valve. The recess 'l ispreferably slightly larger in cross section than the blank i. The lowermember 6 is formed with a long cylindrical recess 9, the inner wall ofwhich is a continuation of the portion of the wall of the recess member5. The recess S is for forming the stem of the valve. The lower inember6 is also provided with a passageway i@ through which a suitabletemperature controlling uid may be passed.

The heated blank is forced through the aperture in the extruding blockto form the blank into a headed cylindrical member. In this operation,the insert 3 is drawn out into the stem portion il formed on the blankand a portion of the insert extends laterally, as at i2, and distributesitself within the head portion I3 formed on the blank.

At the end of the extruding operation, any excess metal of the insertexpands through the end of the recess as shown at ill of Figure 4. Theexcess insert metal is removed to thereby leave a smooth top on the headI3 of the valve.

The valve blank is again heated and forged and machined to the shapeshown in Figure 6.

Figure 5 illustrates a valve blankformed in a slightly different manner.In this case, the blank I having the insert 3 is forced through the dieblock 4 in reversed position in such a manner that the recessed end ofthe blank is extruded through the cylindrical opening 9. In thismodiflcation, the head portion I3 of the blank completely covers theinsert 3 as shown at I5, and the excess metal of the insert is forcedout through the end of the stem as shown at I6. The excess metal I6 isremoved and the recess may be closed in any suitable manner as bywelding a metal piece thereacross.

The heating of the metal of the blank I and the subsequent coolingthereof after the formation of the valve tends to shrink the metal aboutthe insert. This shrinking action, together with the forging operationassures a firm bond between the metals.

Many changes may be made in the design and proportion of the parts andthe arrangement of the steps carrying out this process, and I do notwish to be limited otherwise than is necessary by the prior art and thescope of the appended claims.

I claim as my invention:

1. The method of making a cooled valve which comprises heating a metalblank having a recess therein to expand the metal and recess, forcing acold metallic insert of desired characteristics into the expanded recessand working the composite blank thus formed to form a valve with a headand stem thereon with the insert metal spread out into the head andextending down the stem, said insert being rmly bonded to the blankmetal.

2. The method of forming a metal cooled valve which comprises boring arecess in a metal blank, heating the recessed blank to forgingtemperatures to expand the blank and recess, forcing a cold metal pluginto the recess to completely fill the same and extruding the compositeblank thus formed to form a head and stem thereon with the insert metalspread out into the head, said insert metal being rmly bonded to themetal of the blank.

3. The method of making copper cooled valves which comprises providing ablind bore in a steel blank axially of the blank, said bore extendingfrom one end of the blank into spaced relation from the other endthereof, heating 'the blank to expand the bore, forcing a slug of coldcopper into the recess to ll the same and Working the composite blankthus formed while hot to provide a head and stem thereon with the insertmetal spread out into the head and the excessive amount of metalextending beyond the mouth of the bore and thereafter removing theexcess metal extending beyond the mouth f the bore.

ARCI-IIE T. COLWELL.

